A target polynucleotide is a polynucleotide present in a sample that can be purified from one or more sample components and/or whose presence can be detected using different techniques. Such techniques are typically carried out as part of a diagnostic procedure to detect the presence of a target polynucleotide which is indicative of the presence of an infectious agent or pathogenic condition.
The presence of a target polynucleotide base sequence region, present in a target polynucleotide, can be detected by various methods such as those using nucleic acid probes that hybridize to a target sequence. Probes can be designed to detect different target sequences such as those characteristic of microorganisms, viruses, human genes, plant or animal genes, and/or pathogenic conditions.
A technique for purifying a target polynucleotide, which is often used in diagnostic procedures, involves capturing a target polynucleotide onto a solid support. The solid support retains the target polynucleotide during one or more washing steps of the target polynucleotide purification procedure.
Ranki et al., U.S. Pat. No. 4,486,539 describe a hybridization sandwich technique for capturing and for detecting the presence of a target polynucleotide. The technique involves the capture of the target polynucleotide by a probe bound to a solid support and hybridization of a detection probe to the captured target polynucleotide. Detection probes not hybridized to the target polynucleotide are readily washed away from the solid support. Thus, remaining label is associated with the target polynucleotide initially present in the sample.
Stabinsky, U.S. Pat. No. 4,751,177 describes a method that uses a mediator polynucleotide that hybridizes to both a target polynucleotide and to a polynucleotide fixed on a solid support. The mediator polynucleotide joins the target polynucleotide to the solid support to produce a bound target. A labeled probe can be hybridized to the bound target and unbound labeled probe can be washed away from the solid support.
Englehardt et al, U.S. Pat. Nos. 4,894,324 and 5,288,609, describe a method for detecting a target polynucleotide. The method utilizes two single-stranded polynucleotide segments complementary to the same or opposite strands of the target and results in the formation of a double hybrid with the target polynucleotide. In one embodiment, the hybrid is captured onto a support.
Cape et al., EP Pat. Pub. No. 0 370 694, describe methods and kits for detecting nucleic acids using a solid phase capture means. The methods use oligonucleotide primers labeled with specific binding partners to immobilize primers and primer extension products. The label specifically complexes with its receptor which is bound to a solid support.